Net neutrality should be enshrined in European Union law, says the European Parliament.

On Thursday the Parliament adopted a resolution calling on the European Commission to do more to guarantee an open Internet and net neutrality. Parliamentarians want to see E.U. telecom rules properly and consistently enforced and want internet traffic management practices to be monitored closely in order to "preserve the open and neutral character of Internet."

In April, the European Commission was criticized for not going far enough in its report on net neutrality. Digital Agenda Commissioner Neelie Kroes stopped short of advocating legislation to ensure an open Internet, instead adopting a wait-and-see approach.

There is no set definition of "net neutrality" in the European Union, although the recent Telecoms Package requires that "open and neutral Internet principles are respected in practice." But, as evidenced by Thursday's vote, most members of the European Parliament (MEPs) do not believe this goes far enough.

"Net neutrality and open Internet -- a core principle on which the internet was founded -- is increasingly coming under threat, both in E.U. member states and beyond. The Greens are calling on the European Commission to enshrine net neutrality and the rights of internet users in European legislation, and on Commissioner Kroes to end her ambiguous stance on this vital issue," said Green MEP Philippe Lamberts.

MEPs also asked the Commission to assess whether further regulation is needed to ensure freedom of expression, freedom of access of information, freedom of choice for consumers and media pluralism. An investigation by the Body of European Regulators for Electronic Communications (BEREC) is currently under way and Parliament says the Commission should act within six months of its findings.

One of the key concerns is that end-users' connections may be disrupted by network congestion, and the resolution requires that "Internet service providers do not block, discriminate against or impair the ability of any person to use or offer any service, content or application of their choice irrespective of source or target".

Internet speeds can be reduced by so-called blocking or throttling of traffic. Blocking restricts access to certain services or websites, for example voice-over-IP. Throttling slows down certain types of traffic and affects, for example, the quality of video streaming. The Commission's April report revealed that there has been unequal treatment of data by certain operators.

"Reasonable data traffic management is required and very useful to prevent network congestion and the smooth running of applications and services. Nonetheless, it is clearly understood that traffic management practices must not be used for anti-competitive purposes," said Industry, Research and Energy Committee chairman Herbert Reul from the European Peoples Party.

E.U. ministers plan to adopt conclusions on the open internet and net neutrality in Europe at the Transport, Telecommunications and Energy Council on Dec 13, 2011.